Derogation for increased cattle manure application on grassland in Flanders: effects on crop yield, N export and nitrate-N residues

In September 2015 the European Commission granted the derogation requested by Belgium for the region of Flanders pursuant to Council Directive 91/676/EEC. The derogation implies that under certain conditions a higher amount of livestock manure can be applied. A monitoring network should reveal the impact of derogation on the nitrogen and phosphorus losses from the soil and water quality. In this paper the results of the monitoring network on grassland on sandy and sandy loam soils (2016- 2018) are discussed. No significant effects of the derogation were detected on crop yield and N export in grassland. The average nitrate-N residues in autumn 2016 and 2017 were on average higher on derogation farms. However, the nitrate-N residues were low enough to represent no environmental hazard. In general nitrate-N residues were higher in 2018 compared with 2016 and 2017, largely due to extremely dry summer conditions and sward damage. In 2018 there was no effect of the derogation on nitrate-N
residues in grassland.